The iMainGo iPod speaker is a small, solidly built product that can get surprisingly loud. Sound quality for devices this small is never stellar, but the iMainGo's sound is relatively distortion-free at casual levels, and puts out a much more defined low end than less expensive products like the Kensington FX300. The iMainGo is powered by four AAA batteries and is turned on using a switch found on the interior of its zippered case. The case itself only has enough room for your iPod (or comparably sized MP3 player) and connects to the speaker using a built-in mini-jack connection. There's no speaker volume control, but the iMainGo is designed so that the click-wheel of your iPod faces out the back of the case, allowing you to easily adjust volume and use track controls directly on the player.
Overall, the iMainGo does an admirable job of amplifying your iPod in a very small enclosure. Because the speakers are somewhat exposed and the case material is fabric, the iMainGo is not as weatherproof as the Kensington FX300, but it does provide better sound and a more attractive design.